1. Field of the Invention
The invention relates to a direct evacuation gas fireplace having air intake pipe and gas outlet pipe that are co-linear with each other. The invention also relates to a fireplace having a safety release valve so as to prevent damages to the gas outlet pipe in case of explosion.
2. Discussion of the Related Art
Direct evacuation gas fireplaces or heaters comprise a combustion chamber that is separated from its environment by an enclosure. The enclosure is self-contained inasmuch as it communicates only with the exterior of the house through an air intake pipe that allows air to be taken to the combustion chamber and feed oxygen to the fire. A gas outlet pipe to exhaust the gases that are produced exits from the combustion chamber through the enclosure and outside of the house.
In all existing fireplaces of this type, both pipes are concentric to save space.
However, such a manner of construction implies that the gas outlet coming out of the combustion chamber is placed inside the air intake pipe. In this manner, when the incoming air is cold, the exhaust pipe is cooled by the surrounding air and any water vapour produced by the combustion may condense inside the gas outlet pipe. If the air is cold enough, this water may freeze, thereby blocking, at least partially, the gas outlet pipe.
It has now been found that a co-linear exhaust system for direct evacuation gas fireplaces prevents such problems. In addition, this new system allows introduction of an explosion safety release valve in the gas outlet pipe that could not have been introduced when the pipes were concentric. This valve in the outlet pipe and the use of a flexible conduct for air intake pipe, when submitted to an explosion allows for installation of longer than usual pipes without giving up the safety requirements of the Canadian Gas Association safety requirement test.
Particularly, this test called the "Interim 41" requires that the air inlet pipe, the combustion chamber and the gas outlet pipe of the fireplace be filled with an ideal gas mixture that will generate the most violent explosion possible. To pass the test, the pipes and combustion chamber must resist the explosion without any damages or loss of tightness or imperviousness.